The command "export" crashes in release 0.2.0

[Maurizio Tomasi]

Here is the traceback:

poetry run python manage.py export ./dump
Traceback (most recent call last):
  File "manage.py", line 23, in <module>
    main()
  File "manage.py", line 19, in main
    execute_from_command_line(sys.argv)
  File "/home/tomasi/.cache/pypoetry/virtualenvs/instrumentdb-zDp61lrF-py3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/home/tomasi/.cache/pypoetry/virtualenvs/instrumentdb-zDp61lrF-py3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/tomasi/.cache/pypoetry/virtualenvs/instrumentdb-zDp61lrF-py3.7/lib/python3.7/site-packages/django/core/management/base.py", line 328, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/tomasi/.cache/pypoetry/virtualenvs/instrumentdb-zDp61lrF-py3.7/lib/python3.7/site-packages/django/core/management/base.py", line 369, in execute
    output = self.handle(*args, **options)
  File "/home/tomasi/Documents/work/instrumentdb/browse/management/commands/export.py", line 307, in handle
    if self.use_yaml:
AttributeError: 'Command' object has no attribute 'use_yaml'